Numerous types of emulsifier are known in the art and are used in many emulsion systems, such as, water-in-oil technology or oil-in-water technology and these are are disclosed in McCutcheon's Emulsifiers and Detergents, 1993, North American & International Edition and/or “Emulsions Theory and Practice,” written by P. Becher and published by Oxford University Press, 2001. Typically, water-in-oil surfactants tend to have a low hydrophilic:lipophilic balance (hereinafter referred to as “HLB”), typically less than about 8. Conversely, oil-in-water emulsifiers tend to have higher HLB values of about 8 or more.
The lipophilic component of water-in-oil or oil-in-water emulsifiers, tends to contain less than about 20 carbon atoms or less. It is known that by increasing the length of the lipophilic component in oil-in-water emulsions to less than about 20 carbon atoms results in decreased emulsion stability.
Polyisobutylene succinimide or polyisobutylene succinic anhydride based emulsifiers are well known and are widely used in water-in-oil emulsions or lubricating oils to provide good dispersancy, stabilisation, cleansing and the like. However, due to the lipophilic nature of the polyisobutylene i.e. contains about 20 or more carbon atoms, it is difficult to use these emulsifiers in oil-in-water applications.
International publication WO 03/029309 A2 discloses a hydrophilic emulsifier based on polyisobutylene for use in oil-in-water applications. The emulsifier is made up of (a) a lipophilic part that is derived from a polyisobutylene with a molecular weight between 300 and 10,000; (b) a hydrophilic part containing a polyethylene oxide chain; and (c) a linker derived from polybasic carboxylic acid such as maleic anhydride.
European patent application EP 0 156 572 A2 discloses surfactants derived from (a) a hydrophobic component and (b) a hydrophilic component covalently bonded together. The hydrophilic component further contains an anionic group selected from phosphates, phosphonates, sulphates, sulphonates and carboxymethyl. The hydrophobic component is derived from a polymer of a mono-olefin containing 2 to 6 carbon atoms typically has a molecular weight in the range 400 to 5000. The surfactants disclosed are useful in water-in-oil or oil-in-water emulsions and are incorporated into an oil phase. However, when the surfactants are used in oil-in-water emulsions, they tolerate being dispersed in water phases which are high in dissolved inorganic matter, for example, magnesium chloride or calcium chloride.
U.S. Pat. No. 4,776,966 discloses a drilling fluid composition of an invert oil-based type emulsions that contains block or graft copolymers that are produced from polycarboxylic acids and a hydrophobic component derived from a mono-olefin and maleic anhydride. The maleic anhydride can be further reacted with compounds containing hydroxyl or amino groups, for example polyols or polyamines. However, the composition is only suitable for use in emulsions of brine-in-oil because it requires dissolved inorganic matter for emulsion stabilisation.
U.S. Pat. No. 4,708,753 discloses water-in-oil emulsions that contain as emulsifiers, mono- or diamine salts of succinic acid or monoamine salts of succinic acid half-esters or succinic acid half-amides. The half-esters or half-amides are prepared by reacting alkanolamines, polyamines, oligoalcohols or polyols with hydrocarbyl substituted succinic acid anhydrides. The hydrocarbyl contains 20 to 500 carbon atoms, for example, polyisobutylene. However, the emulsifier composition is only suitable for use in water-in-oil emulsions.
It would be desirable to have an amphiphilic compound containing a lipophilic component suitable for use in oil-in-water emulsions. The present invention provides an amphiphilic compound with a lipophilic component suitable for use in oil-in-water emulsions.
It would be desirable to have an amphiphilic compound containing a lipophilic component that is capable of dispersing in an aqueous phase. The present invention provides an amphiphilic compound containing a lipophilic component that is capable of dispersing in an aqueous phase.
It would be desirable to have an amphiphilic compound containing a hydrophilic component sufficient to provide water dispersibility or solubility to the amphiphilic compound though it contains a lipophilic component containing about 20 or more carbon atoms.
It would be desirable to have an amphiphilic compound containing a lipophilic component capable of forming a storage stable emulsion that does not require a brine stabiliser. The present invention provides an amphiphilic compound containing a lipophilic component capable of forming a storage stable emulsion that does not require a brine stabiliser.